1. Field of the Invention
The present invention relates to an object observation system and a method of controlling an object observation system.
2. Description of Related Art
Endoscope apparatuses have been widely used in medical fields and industrial fields. In the endoscope apparatus, an endoscopic image obtained by a television camera externally installed endoscope in which a television camera is attached to an eyepiece portion of an optical endoscope or an electronic endoscope self-containing an image pickup apparatus at the distal end of an insert portion thereof is displayed on a monitor. With reference to the endoscopic image, observation and/or treatment may be performed.
An endoscopic surgery system using the endoscope apparatus is used for performing an operation under endoscopic observation by using a pneumoperitoneum apparatus and/or a high-frequency cautery apparatus, for example, as multiple peripheral apparatuses in addition to a camera control unit (called CCU or video processor, hereinafter) including a light source apparatus for supplying illumination light to an endoscope and/or a video signal processing circuit for displaying endoscopic images and/or a TV monitor for displaying endoscopic images. In the endoscopic surgery system, the multiple peripheral apparatuses are connected to a system controller in order to centrally control the multiple peripheral apparatuses.
With the recent increase in processing speed of computers, the endoscopic surgery system can reconstruct a volume rendering image (simply called rendering image or VR image, hereinafter) as a virtual three dimensional image (called virtual image, hereinafter) instantly by using medical image data in a three-dimensional area and can display a rendering image on a display screen of the monitor as a navigation image for guiding an endoscope, for example, to a target part of a body to be examined and/or a reference image for checking the surroundings of a target part.
As this kind of conventional endoscopic surgery system, a system used in a bronchial endoscope apparatus has been proposed as disclosed in Japanese Unexamined Patent Application Publication No. 2000-135215.
The endoscopic surgery system disclosed in the publication creates a three dimensional image of a tract within a body to be examined based on medical image data in a three-dimensional area of the body to be examined, obtains a path to a target point along the tract on the three-dimensional image, creates a virtual rendering image of the tract along the path based on the medical image data and displays the virtual rendering image on the monitor. Thus, a bronchial endoscope can be guided or navigated to a target part.
With the endoscopic surgery system used in the bronchial endoscope apparatus, a rendering image of a predetermined path is displayed. In this case, an operator does not have to operate or instruct in the middle in particular. Therefore, the endoscopic surgery system is useful for navigating the bronchial endoscope to a tract in the body such as the bronchial tubes, which limits a direction of line of vision.
On the other hand, a conventional endoscopic surgery system can display a rendering image as a reference image in addition to an endoscopic image when the conventional endoscopic surgery system is used for surgery.
Generally, in surgery, an operator performs surgical treatment by using a treating device such as an electric knife with reference to an endoscopic image. In this case, the operator uses rendering images of a target part and the surroundings as reference images in order to check the state of the blood vessels around an internal organ and/or the back of an internal organ.
Therefore, the endoscopic surgery system must display a rendering image as a reference image that an operator needs to check on the spot during surgery more than a case where a rendering image is used for navigation of a bronchial endoscope, for example.
Therefore, the conventional endoscopic surgery system displays a rendering image in response to a manipulation on a mouse and/or a keyboard by a nurse or an operator in an unclean area based on an instruction by an operator in a clean area.
Recently, in a surgical operation, various progressions and results of the surgery are often recorded, and endoscopic images may be also recorded. During surgery, an operator takes photographs by manipulating a release switch in order to store in patient's charts and records and saves still-image data of endoscopic images as a record of the surgery.
In order to create a three-dimensional image as described above, a three-dimensional virtual image data of the inside of a body to be examined is obtained by picking up a tomographic image of the body to be examined by using an X-ray computed topography (CT) apparatus, for example. Thus, an affected part can be diagnosed by using the virtual image data.
In the CT apparatus, X-ray irradiation/detection are rotated continuously, and, at the same time, a body to be examined is fed in series in the body axis direction. Thus, continuous helical scanning can be performed on a three-dimensional area of the body to be examined. Therefore, a three-dimensional virtual image can be created from tomographic images of serial slices of the three-dimensional area.
One of this kind of three dimensional image is a three dimensional image of the bronchi of the lung. A three-dimensional image of the bronchi is used for three-dimensionally identifying a position of an abnormal part, which is suspected as a lung cancer, for example. In order to check the abnormal part by performing a biopsy, a bronchial endoscope is inserted, and a biopsy needle and/or a biopsy forceps are extended at the distal end. Thus, a tissue thereof can be sampled.
In a tract inside of the body having multi-level branches such as the bronchi, when a position of an abnormal part is close to the end of the branch, bringing the distal end of an endoscope to a target part accurately in a short period of time is difficult. Therefore, for example, a navigation apparatus is proposed in Japanese Unexamined Patent Application Publication No. 2000-135215 above.
By the way, for a diagnosis on an internal organ of the abdomen area, which is a body to be examined, an image analysis software is conventionally in actual use which creates a three-dimensional virtual image of the body to be examined within the abdomen area mainly as described above and displays the image for diagnosis.
An image system using this kind of image analysis software is used for diagnosis so that a doctor can identify a change in a lesion of a body to be examined within the abdomen area of a patient before surgery, and the diagnosis is generally performed on a desk.